Distributed pole planetary rotor permanent magnet motor

Abstract

The present invention discloses a distributed magnetic pole planetary rotor permanent magnet motor, which belongs to the technical field of electric motors. The distributed magnetic pole planetary rotor permanent magnet motor includes a casing and multiple stators, and also includes: a sun shaft, which is pivotally connected to the casing shaft; multiple planetary rotors, the multiple planetary rotors are evenly distributed on the periphery of the sun shaft, each planetary rotor corresponds to a stator, each planetary rotor includes a planetary shaft, an iron core and a permanent magnet, the planetary shaft is pivotally connected to the casing shaft, the iron core is connected to one end of the planetary shaft, the permanent magnet is arranged on the iron core, and the other end of the planetary shaft is geared with the sun shaft. The distributed magnetic pole planetary rotor permanent magnet motor of the present invention utilizes multiple planetary rotors to jointly drive the sun shaft to rotate, thereby reducing the size of the body and the mechanical stress of the motor under the premise of improving the torque and power density, which is conducive to the high-speed and stable operation of the hub motor drive system.

Description

Technical Field

[0001] The present invention relates to the technical field of electric motors, and in particular to a distributed magnetic pole planetary rotor permanent magnet motor. Background Art

[0002] Since the beginning of the 21st century, electric vehicles have become increasingly popular in people's lives. In order to improve the overload capacity of electric vehicle electric drive systems, high-speed permanent magnet hub motor acceleration and reduction solutions are often used to improve torque and power density. In addition, the integration level of various parts of the motor drive system is also further improved.

[0003] The power module in a traditional electric vehicle is generally designed and placed separately with a reducer and a high-speed permanent magnet hub motor. The output end of the high-speed permanent magnet hub motor is connected to the reducer. The output end of the high-speed hub motor rotates at a high speed. After being decelerated by the reducer, the torque of the entire power module can be increased.

[0004] However, the existing split power module not only adds extra space and volume, but also, in order to ensure the power density of the high-speed permanent magnet hub motor, the outer diameter of the high-speed permanent magnet hub motor rotor is generally larger, which will generate greater mechanical stress when the rotor rotates, which is not conducive to the high-speed and stable operation of the high-speed permanent magnet hub motor drive system. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems in the prior art and provide a distributed magnetic pole planetary rotor permanent magnet motor, which drives multiple planetary rotors to rotate simultaneously through multiple stators, and utilizes multiple planetary rotors to jointly drive the sun shaft to rotate, thereby reducing the body size and the mechanical stress of the motor while improving the torque and power density, thereby facilitating the high-speed and stable operation of the hub motor drive system.

[0006] The present invention provides a distributed magnetic pole planetary rotor permanent magnet motor, comprising a housing and a plurality of stators, and further comprising:

[0007] A sun shaft, pivotally connected to the housing;

[0008] A plurality of planetary rotors are evenly distributed on the periphery of the sun shaft, each planetary rotor corresponds to a stator, each planetary rotor comprises a planetary shaft, an iron core and a permanent magnet, the planetary shaft is pivotally connected to the housing shaft, the iron core is connected to one end of the planetary shaft, the permanent magnet is arranged on the iron core, the other end of the planetary shaft is gear-connected with the sun shaft, and the permanent magnet on each planetary rotor is arranged on the inner side of the corresponding stator.

[0009] Preferably, the relationship between the pole pair number pr of the permanent magnet on each planetary rotor and the equivalent pole pair number ps of the armature magnetic field generated by the stator is pr=ps=p, where p is a positive integer, the number of phases of the stator is m, the number of planetary rotors is n, m and n are both positive integers greater than or equal to 2, and a symmetrically distributed sinusoidal current is passed through each phase of the stator.

[0010] Preferably, the mechanical angle difference between adjacent planetary rotors is 2π / n, the mechanical angle difference between magnetic pole center lines is 2π×k / (n×p), the value of parameter k needs to be 0 or 2p, and the functional relationship between n and m, p needs to satisfy n=l×GCD(n,p)×m, GCD(n,p) is the greatest common divisor of n and p, and l is a positive integer.

[0011] Preferably, symmetrically distributed multi-phase currents are passed through the multiple stators, and the phase difference between two adjacent phase currents is h×2π / m, where h is a positive integer ranging from 1 to m-1. When the phase difference angles of the center lines of the magnetic poles of the planetary rotors of the motor are different, the current phase sequence in the winding is also different.

[0012] Preferably, the multiple stators are divided into two rows, the left row of stators is arranged on the left side of the casing, and the right row of stators is arranged on the right side of the casing. Each planetary rotor is provided with two groups of iron cores and permanent magnets, one group of iron cores and permanent magnets is arranged on the left side of the planetary shaft, and the other group of iron cores and permanent magnets is arranged on the right side of the planetary shaft. The iron cores and permanent magnets on the left side are arranged on the inner side of the left row of stators, and the iron cores and permanent magnets on the right side are arranged on the inner side of the right row of stators. The sun shaft is gear-connected between the iron cores and permanent magnets on the left and right sides of the planetary shaft.

[0013] Preferably, each planetary shaft is provided with a gear, the number of teeth of the gears on each planetary shaft is the same, and each planetary shaft is meshed with the sun shaft through the gear thereon.

[0014] Preferably, a ring gear is provided on the sun shaft, and each planetary shaft is meshed with the ring gear via a gear thereon.

[0015] Preferably, the casing includes a left end cover, a left shell, a right shell and a right end cover, the left end cover is arranged on the left side of the left shell, the right end cover is arranged on the right side of the right shell, the right side of the left shell is connected to the left side of the right shell, one end of the sun shaft is pivotally connected to the left end cover, and the other end of the sun shaft is pivotally connected to the middle part of the left shell, one end of each planetary shaft is pivotally connected to the left end cover, and the other end of each planetary shaft is pivotally connected to the right end cover.

[0016] Preferably, the permanent magnet adopts a surface type and a built-in type structure.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: the distributed magnetic pole planetary rotor permanent magnet motor of the present invention drives multiple planetary rotors to rotate simultaneously through multiple stators, and utilizes multiple planetary rotors to jointly drive the sun shaft to rotate, thereby reducing the body size and the mechanical stress of the motor while improving the torque and power density, which is beneficial to the high-speed and stable operation of the hub motor drive system.

[0018] When pr=ps=p, the fundamental back electromotive force of the motor is the largest, which can improve the power density of the motor. Setting m and n to positive integers greater than or equal to 2 can meet the economic requirements while meeting the power density of the motor. When the driving voltage and current meet the above-mentioned relationship of equal amplitude, same phase sequence, and uniform phase distribution, the motor can effectively utilize the bus voltage of the driver and can output a stable electromagnetic torque. The DC component of the output torque on the sun shaft is the product of the sum of the DC components of the output torque of each planetary rotor and the reduction ratio, which can eliminate the double frequency pulsating component and achieve a stable electromagnetic torque output. Multiple stators are divided into two rows on the left and right, and the iron cores and permanent magnets on the left and right sides jointly drive the planetary shaft to rotate, thereby driving the entire planetary rotor to rotate, which can further improve the output torque of the entire motor and the stability of the output torque. When each planetary shaft rotates, it drives the sun shaft to rotate through its own gear. By setting the number of teeth on the gears on each planetary shaft to be the same, it can ensure that the driving force applied by each planetary shaft to the sun shaft is balanced, thereby further improving the stability of the motor during high-speed movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a first embodiment of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a second embodiment of the present invention;

[0021] Figure 3 It is a structural schematic diagram of a third embodiment of the present invention;

[0022] Figure 4 A schematic diagram of the waveforms of the motor stator armature winding and its corresponding back electromotive force and current of the present invention;

[0023] Figure 5 It is a schematic diagram of the motor rotor and its corresponding torque waveform of the present invention.

[0024] Description of reference numerals:

[0025] 101. Casing, 102. Stator, 103. Sun shaft, 104. Planetary rotor, 105. Planetary shaft, 106. Iron core, 107. Permanent magnet, 2. Gear, 3. Ring gear, 401. Left end cover, 402. Left shell, 403. Right shell, 404. Right end cover. DETAILED DESCRIPTION

[0026] The following is combined with Figure 1-5 , the specific implementation of the present invention is described in detail, but it should be understood that the protection scope of the present invention is not limited by the specific implementation. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] like Figure 1-5 As shown, the distributed magnetic pole planetary rotor permanent magnet motor provided by the present invention includes a casing 101 and a plurality of stators 102, and also includes: a sun shaft 103 and a plurality of planetary rotors 104, the sun shaft 103 is pivotally connected to the casing 101; a plurality of planetary rotors 104, the plurality of planetary rotors 104 are evenly distributed on the periphery of the sun shaft 103, each planetary rotor 104 corresponds to a stator 102, each planetary rotor 104 includes a planetary shaft 105, an iron core 106 and a permanent magnet 107, the planetary shaft 105 is pivotally connected to the casing 101, the iron core 106 is connected to one end of the planetary shaft 105, the permanent magnet 107 is arranged on the iron core 106, the other end of the planetary shaft 105 is gear-connected to the sun shaft 103, and the permanent magnet 107 on each planetary rotor 104 is arranged on the inner side of the corresponding stator 102.

[0028] The working principle of the above embodiment is briefly described:

[0029] The size and structure of each planetary rotor 104 of this motor are the same, and the eccentricity between the geometric center of the rotor and the geometric center of the stator 102 is the same. Gears 2 are provided on both the planetary shaft 105 and the sun shaft 103. The stator 102 and multiple planetary rotors 104 are coaxially mounted together, and a structure of outer stator 102 and inner planetary rotor 104 is adopted. When this motor is in use, a symmetrically distributed sinusoidal current is passed into each phase of the stator 102. Each phase of the stator 102 generates an armature magnetic field generated by the winding, which drives the iron core 106 and permanent magnet 107 of the planetary rotor 104 corresponding to the inner side thereof to rotate, thereby driving the planetary shaft 105 to rotate, and multiple rotating planetary shafts 105 simultaneously drive the sun shaft 103 to rotate, thereby being able to play a role in improving torque and power density.

[0030] The distributed magnetic pole planetary rotor permanent magnet motor of the present invention drives multiple planetary rotors 104 to rotate simultaneously through multiple stators, and utilizes multiple planetary rotors 104 to jointly drive the sun shaft 103 to rotate, thereby reducing the body size and the mechanical stress of the motor while improving the torque and power density, which is beneficial to the high-speed and stable operation of the hub motor drive system.

[0031] On the basis of the above embodiments, in order to improve the power density of the motor, and under the premise of meeting the power density of the motor, the economic demand is taken into consideration.

[0032] like Figure 4 and 5 As shown, the relationship between the pole pair number pr of the permanent magnet 107 on each planetary rotor 104 and the equivalent pole pair number ps of the armature magnetic field generated by the stator 102 is pr=ps=p, p is a positive integer, the number of phases of the stator 102 is m phases, the number of the planetary rotors 104 is n, m and n are both positive integers greater than or equal to 2, and symmetrically distributed sinusoidal currents are passed through each phase of the stator 102.

[0033] When pr=ps=p, the fundamental back electromotive force of the motor is the largest, thereby improving the power density of the motor. The motor needs to output as large an electromagnetic torque as possible within a limited size space to ensure the high power density requirement. The larger the value of n, the more planetary rotors 104 there are, and the higher the power density can be, but the more permanent magnets 107 are used. Setting both m and n to positive integers greater than or equal to 2 can take into account the economic requirements while meeting the power density of the motor.

[0034] As a preferred solution, Figure 4 and 5 As shown, the mechanical angle difference between adjacent planetary rotors 104 is 2π / n, the mechanical angle difference between the magnetic pole center lines is 2π×k / (n×p), the parameter k must be 0 or 2p, and the functional relationship between n and m, p must satisfy n=l×GCD(n,p)×m, GCD(n,p) is the greatest common divisor of n and p, and l is a positive integer. When the permanent magnet hub motor system for electric vehicles is actually working, it often uses three-phase m=3 drive inverter power supply. Under the condition of m=3, the minimum value of n can be selected as 3, that is, the driving voltage of each phase is obtained by pulse width modulation. If the amplitude of each phase voltage is different or the phase is unevenly distributed, on the one hand, the DC bus voltage cannot be effectively utilized, and on the other hand, the double frequency pulse component of the planetary rotor 104 cannot be eliminated, which needs to be avoided in the actual system. When the fundamental amplitude of the driving voltage of each phase is the same and the phase difference is 2π / 3, a three-phase current with equal amplitude, the same phase sequence and a phase difference of 2π / 3 can be obtained on the motor stator 102. For each planetary rotor 104, the DC component can be directly added, and the double frequency pulsation component differs by 2π / 3 and can be eliminated when summing. When the driving voltage and current meet the above-mentioned relationship of equal amplitude, same phase sequence and uniform phase distribution, the motor can effectively utilize the bus voltage of the driver and can output a stable electromagnetic torque.

[0035] As a preferred solution, Figure 4 and 5As shown, symmetrically distributed multi-phase current is passed through the multiple stators 102, and the phase difference between two adjacent phase currents is h×2π / m, where h is a positive integer ranging from 1 to m-1. When the phase difference angles of the magnetic pole center lines of the planetary rotors 104 of the motor are different, the current phase sequence in the winding is also different.

[0036] In this embodiment, the parameter k is 0 or 2p, and the functional relationship between n and m, p must satisfy n=l×GCD(n, p)×m, GCD(n, p) is the greatest common divisor of n and p, and l is a positive integer. The mathematical relationship specifically includes the following combinations: n=3, m=3, p=1; n=3, m=3, p=2; n=3, m=3, p=4; n=4, m=4, p=1; n=4, m=4, p=3……. When the motor is working normally, a symmetrical multi-phase current is passed through the stator 102, and the phase difference between the adjacent two-phase currents is h×2π / m, where h is a positive integer and the value range is 1 to m-1. When the phase difference angles of the center lines of the magnetic poles of the planetary rotors 104 of the motor are different, the current phase sequence in the winding is also different. When the parameter k is 0, h is 1; when the parameter k is 2p, h is m-1. At this time, the phase sequence of the voltage at the end of the m-phase winding is the same as the phase sequence of the current, and each planetary rotor 104 can synthesize a stable electromagnetic torque. For example, the structure when n=3, m=3, p=1, k=0. The waveforms of the back electromotive force and the current in the stator 102 are as follows: Figure 4 The electromagnetic torque output by each planetary rotor 104 is as follows: Figure 5 As shown. Figure 5 It can be seen from the results in that the electromagnetic torque output by each planetary rotor 104 mainly includes a DC component and a double fundamental frequency pulsating component. When the planetary shaft 105 is meshed with the sun shaft 103, the torque output by each planetary shaft 105 is summed to obtain the output torque on the sun shaft 103. The DC component of the output torque on the sun shaft 103 is the product of the sum of the DC components of the output torque of each planetary rotor 104 and the reduction ratio, which can eliminate the double fundamental frequency pulsating component and achieve a stable electromagnetic torque output.

[0037] As a preferred solution, Figure 1As shown, the multiple stators 102 are divided into two rows, the left row of stators 102 is arranged on the left side of the casing 101, and the right row of stators 102 is arranged on the right side of the casing 101. Two groups of iron cores 106 and permanent magnets 107 are provided on each planetary rotor 104, one group of iron cores 106 and permanent magnets 107 are arranged on the left side of the planetary shaft 105, and the other group of iron cores 106 and permanent magnets 107 are arranged on the right side of the planetary shaft 105. The iron cores 106 and permanent magnets 107 on the left side are arranged on the inner side of the left row of stators 102, and the iron cores 106 and permanent magnets 107 on the right side are arranged on the inner side of the right row of stators 102. The sun shaft 103 is toothed between the iron cores 106 and permanent magnets 107 on the left and right sides of the planetary shaft 105. The multiple stators 102 are divided into two rows, left and right. When the stators 102 in the left row are energized, they drive the iron core 106 and the permanent magnet 107 on the left side of the planetary rotor 104 to rotate. When the stators 102 in the right row are energized, they drive the iron core 106 and the permanent magnet 107 on the right side of the planetary rotor 104 to rotate. The iron cores 106 and the permanent magnets 107 on the left and right sides jointly drive the planetary shaft 105 to rotate, thereby driving the entire planetary rotor 104 to rotate. The sun shaft 103 is gear-connected between the iron cores 106 and the permanent magnets 107 on the left and right sides of the planetary shaft 105. The multiple planetary rotors 104 jointly drive the sun shaft 103 to rotate, thereby further improving the output torque of the entire motor and the stability of the output torque.

[0038] As a preferred solution, Figure 1 As shown, each planetary shaft 105 is provided with a gear 2, and the gears 2 on each planetary shaft 105 have the same number of teeth, and each planetary shaft 105 is meshed with the sun shaft 103 through the gears 2 thereon. When each planetary shaft 105 rotates, it drives the sun shaft 103 to rotate through its own gear 2. By setting the number of teeth of the gears 2 on each planetary shaft 105 to be the same, it can ensure that the driving force applied by each planetary shaft 105 to the sun shaft 103 is balanced, thereby further improving the stability of the motor during high-speed movement.

[0039] As a preferred solution, Figure 3 As shown, a ring gear 3 is provided on the sun shaft 103, and each planet shaft 105 meshes with the ring gear 3 through a gear 2 thereon. The gears 2 on the planet shaft 105 and the sun shaft 103 can be realized by spur gear or helical gear. By providing the ring gear 3 on the sun shaft 103, not only can the electromagnetic torque provided by each planetary rotor 104 be summed and the double frequency pulse component be eliminated, but also the obtained stable electromagnetic torque can be output from the sun shaft 103. And because the gears 2 mesh with each other, the relative position of the center line of the magnetic poles of each permanent magnet planetary rotor 104 in the motor can remain unchanged during operation.

[0040] As a preferred solution, Figure 1-3As shown, the casing includes a left end cover 401, a left housing 402, a right housing 403 and a right end cover 404. The left end cover 401 is arranged on the left side of the left housing 402, and the right end cover 404 is arranged on the right side of the right housing 403. The right side of the left housing 402 is connected to the left side of the right housing 403. One end of the sun shaft 103 is pivotally connected to the left end cover 401, and the other end of the sun shaft 103 is pivotally connected to the middle of the left housing 402. One end of each planetary shaft 105 is pivotally connected to the left end cover 401, and the other end of each planetary shaft 105 is pivotally connected to the right end cover 404. By configuring the casing 101 as the left end cover 401, the left housing 402, the right housing 403 and the right end cover 404, the installation and removal of the sun shaft 103 in the casing 101 can be facilitated, thereby facilitating the installation and maintenance of the entire motor.

[0041] As a preferred solution, Figure 1-3 As shown, the permanent magnet 107 adopts a surface-type and built-in structure.

[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A distributed magnetic pole planetary rotor permanent magnet motor, comprising a housing (101) and a plurality of stators (102), characterized in that: Also includes: A sun shaft (103) is pivotally connected to the housing (101); A plurality of planetary rotors (104), the plurality of planetary rotors (104) being evenly distributed on the periphery of the sun shaft (103), each planetary rotor (104) corresponding to a stator (102), each planetary rotor (104) comprising a planetary shaft (105), an iron core (106) and a permanent magnet (107), the planetary shaft (105) being pivotally connected to the housing (101), the iron core (106) being connected to one end of the planetary shaft (105), the permanent magnet (107) being arranged on the iron core (106), the other end of the planetary shaft (105) being gear-connected to the sun shaft (103), and the permanent magnet (107) on each planetary rotor (104) being arranged on the inner side of the stator (102) corresponding thereto; The relationship between the number of pole pairs pr of the permanent magnet (107) on each planetary rotor (104) and the number of equivalent pole pairs ps of the armature magnetic field generated by the stator (102) is pr=ps=p, wherein p is a positive integer, the number of phases of the stator (102) is m phases, the number of the planetary rotors (104) is n, and both m and n are positive integers greater than or equal to 2, and a symmetrically distributed sinusoidal current is passed through each phase of the stator (102); The mechanical angle difference between adjacent planetary rotors (104) is 2π / n, the mechanical angle difference between magnetic pole center lines is 2π×k / (n×p), the value of parameter k must be 0 or 2p, and the functional relationship between n and m, p must satisfy n=l×GCD(n, p)×m, GCD(n, p) is the greatest common divisor of n and p, and l is a positive integer; A symmetrically distributed multi-phase current is passed through the multiple stators (102), the phase difference between two adjacent phase currents is h×2π / m, h is a positive integer, and the value range is 1 to m-1. When the phase difference angles of the magnetic pole center lines of the planetary rotors (104) of the motor are different, the current phase sequence in the winding is also different; When the parameter k is 0, h is 1; when the parameter k is 2p, h is m-1.

2. The distributed magnetic pole planetary rotor permanent magnet motor according to claim 1, characterized in that: The plurality of stators (102) are divided into two rows, the left row of stators (102) being arranged on the left side of the housing (101), and the right row of stators (102) being arranged on the right side of the housing (101). Each planetary rotor (104) is provided with two groups of iron cores (106) and permanent magnets (107), one group of iron cores (106) and permanent magnets (107) being arranged on the left side of the planetary shaft (105), and the other group of iron cores (106) and permanent magnets (107) being arranged on the left side of the planetary shaft (105). The permanent magnet (107) is arranged on the right side of the planetary shaft (105), the iron core (106) and the permanent magnet (107) on the left side are arranged on the inner side of the stator (102) in the left row, and the iron core (106) and the permanent magnet (107) on the right side are arranged on the inner side of the stator (102) in the right row, and the sun shaft (103) is gear-connected between the iron core (106) and the permanent magnet (107) on the left and right sides of the planetary shaft (105).

3. The distributed magnetic pole planetary rotor permanent magnet motor according to claim 1, characterized in that: Each planetary shaft (105) is provided with a gear (2), the gears (2) on each planetary shaft (105) have the same number of teeth, and each planetary shaft (105) is meshed with the sun shaft (103) via the gear (2) thereon.

4. The distributed magnetic pole planetary rotor permanent magnet motor according to claim 1, characterized in that: A ring gear (3) is provided on the sun shaft (103), and each planet shaft (105) is meshed with the ring gear (3) via a gear (2) thereon.

5. The distributed magnetic pole planetary rotor permanent magnet motor according to claim 1, characterized in that: The casing comprises a left end cover (401), a left shell (402), a right shell (403) and a right end cover (404); the left end cover (401) is arranged on the left side of the left shell (402); the right end cover (404) is arranged on the right side of the right shell (403); the right side of the left shell (402) is connected to the left side of the right shell (403); one end of the sun shaft (103) is pivotally connected to the left end cover (401); the other end of the sun shaft (103) is pivotally connected to the middle part of the left shell (402); one end of each planetary shaft (105) is pivotally connected to the left end cover (401); and the other end of each planetary shaft (105) is pivotally connected to the right end cover (404).

6. The distributed magnetic pole planetary rotor permanent magnet motor according to claim 1, characterized in that: The permanent magnet (107) adopts a surface type and built-in type structure.

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